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Re: The Case Against Imidicloprid

One thing I'm still trying to puzzle out is why the big difference in toxicity between the two crustaceans in the Sanchez-Bayo paper. If this stuff acts on a nervous system, what's so different? Both absolute level and time dependence are very different. One thought I had was either an absence or presence of another pathogen. The particularly strong time dependence is associated with the decay of the host immune system and the growth of pathogen organisms. You might expect very different results depending if pathogens are present or not. This kind of goes along with the very different results for toxicity from different researchers on bees, and also with the "outbreaks" of CCD that tend to happen. You might expect very different outcomes depending on exposure levels, pathogens, and time the bees need to live.

Re: The Case Against Imidicloprid

Originally Posted by Kieck

I'm convinced that bees do not collect much corn pollen under normal conditions. I've spent thousands of hours counting various insects in corn throughout the season. Honeybees are largely absent from cornfields at most times. I suspect that bees only collect corn pollen when other sources of pollen are very scarce or have failed.

My experience from keeping bees with fields of maize nearby:

During maize flowering time lots of bees coming home with very large pale pollen packs in during a few hours in the morning.
The pollen collection on maize only happens during a short daily window, but the amounts brought hoe during that time are large, as nearly every pllen load is from maize.
The flowering period is the middle/late summer, a time when few other pollen sources are available.

As for observing bees whilst they collect the pollen:
The maize fields are usually huge, so you would need a major apiary nearby to see bees out in force and you would need to be there just at the right time.

What about the stores left behind in hives that have died from CCD? My understanding is that leaving behind adequate to large amounts of stores is a symptom of CCD. In fact, I've read and heard that new bees put into a hive that collapsed from CCD are also likely to suffer the same fate rapidly (if they can even be enticed to take up residence in the hive). What would cause such a symptom if the pesticide residues are all gone?

I agree that the guttation is not usually a problem.

With regards to the leftover stores I think we simply lack data:

Most beekeepers are told that if they suspect poisonig they need to send in bees.
With most of the bees gone from a CCD hive this is usually not an option.
If all beekeepers were encouraged to have leftover stores analyzed we might see interesting results, but from what I have read in studies it is somewhat difficult to analyze sticky liquids like HFCS for traces of neonics at the ppb range.

My advice:

Look for the maize pollen arriving at the hives during flowering time, you could also set up a pollen trap for a day.
You might be surprised at the amounts actually brought in!

Re: The Case Against Imidicloprid

My own observations are backed up by some studies:

...
Malerbo e Couto (1992) studied the activity of bees Africanized, Jaboticaba l, São Paulo State, noted that about half of the pollen was collected in the field until 10:00 a.m.
...
According Sabugosa-Madeira et al. (2007), bees do not show great interest in the fields of corn plants when there are other good sources of pollen to ensure close and their livelihoods. However, the bees come to feed almost exclusively on corn pollen when in case of famine or when apiaries are located in areas with large plantations of corn (MAURIZIO; LOUVEAUX, 1965). These authors found apiaries in the area of the Landes, in France, satisfying about 90% of its needs for flowers with pollen from corn, extending this for almost a month until the end of August.
...

Re: The Case Against Imidicloprid

The flowering period is the middle/late summer, a time when few other pollen sources are available. -Stromnessbees

Difference in location may explain a lot here. Corn tassels and produces pollen during a window of about two weeks each year around here. And enough other flowers are usually in bloom during that time.

In the fields where I've collected data, an apiary of 64 hives was within a mile each time, often within 1/4 mile depending on the field. Flowers around the corn fields were often humming with bees. They just don't seem to venture into corn much here.

Most beekeepers are told that if they suspect poisonig they need to send in bees. -Stromnessbees

The recommendation I've seen, most recently from our state apiarist, is to collect honey and pollen samples from hives where CCD is observed to submit the samples for pesticide and pathogen testing.

According Sabugosa-Madeira et al. (2007), bees do not show great interest in the fields of corn plants when there are other good sources of pollen to ensure close and their livelihoods. -contained in quote posted by Stromnessbees

That matches with what I've observed. How do you tease out "poor nutrition" from "trace amounts of neonicotinoids" in an analysis of bees in this sort of situation? Which one is more important than the other?

Re: The Case Against Imidicloprid

Originally Posted by Kieck

How do you tease out "poor nutrition" from "trace amounts of neonicotinoids" in an analysis of bees in this sort of situation? Which one is more important than the other?

The bees in the valley where CCD appeared suddenly had been feeding on maize pollen for years and were thriving.
Bees tend to compensate for low amino acid content by collecting more of the pollen, and in our experience this worked fine, colony losses over winter were virtually unknown.

After the introduction of Clothianidin treated maize whole apiaries were lost to CCD in the following winter, nothing else had changed and the weather had been quite average.

This seed treated maize had been banned in Germany where it had caused massive colony losses, and remaining stockpiles were sold over the border to Austria, making sure it wouldn't go to waste.

As one could have expected, CCD 'arrived' just as it had in the years before in Germany.

Re: The Case Against Imidicloprid

Bees tend to compensate for low amino acid content by collecting more of the pollen, .... -Stromnessbess

Sure, but from corn (maize)? From everything I've observed, they only seem to collect significant amounts of corn pollen in times of desperation. Your observations suggest that my generalization based on what I've seen in this region does not extend to that valley in Austria, at least.

After the introduction of Clothianidin treated maize whole apiaries were lost to CCD in the following winter, nothing else had changed and the weather had been quite average. -Stromnessbees

The title of the thread is specifically about imidacloprid, not clothianidin. However, I recognize the similarities of the two insecticides, and I won't belabor that point.

I envy the sort of conditions where you must have been keeping bees. I have yet to have a year of keeping bees that I could point to as being "average." Each year here seems to provide some sort of remarkable climatic condition: too wet, too dry, too hot, too cold, wet spring and dry summer, up-and-down temperatures during the winter, deep snow, and so on.

Having said that, did you submit samples of honey and/or pollen from those collapsed hives for testing to see if clothianidin was detectable in them? Seems to me that that would have provided damning evidence, given everything else that you outlined here.

Currently, the bees are doing comparatively well, said Gottfried Wenzel, Vice president of the Regional Beekeeper Association. "This year we have rarely had any reports of losses and we hope that it will be better than the previous year."

Re: The Case Against Imidicloprid

Originally Posted by grondeau

If you are wondering why we don't see residue in collapsed colonies, the answer is that the effects happen at unobservably small chronic doses.

In the USA we don't see a pattern of consistently more collapsed colonies in states where acreage of crops planted in crops grown from neonic treated seed is high (e.g. North and South Dakota) vs States where the acreage is low. So it stands to reason that if neonics were banned in the USA, the ongoing problem of 25% of the beekeepers losing 40-100% of their colonies each year would continue.

Re: The Case Against Imidicloprid

I think neonic poisoning is a 'sexy' cause for hive death/CCD. Most people claiming CCD don't regularly monitor varroa mite levels. I think in many cases it is easier to blame a pesticide for the lose of hives than to take the time to monitor and control mites.

Tom[/QUOTE]

I had my hives near treated imidicloprid orange trees for Orange Blossom honey production, I harvested some supers, and extracted some of it and others I stored for winter feed. hives that i gave a super of orange blossom lagged to build up as they went into the honey stores, where other hives build up quickly because they weren't given that Orange Honey super. It didn't kill the colony but they were behind in population compared to my other hives that they weren't ready for Avocado pollination/honey production, it was until then they began to explode in population after they consumed the stored honey (I havent tested the honey, no Lab wanted to do it, would have been Interesting to see). I also had hives near young lemons treated with Imidicloprid they made some honey, but didn't get sick at all, even if I left it there for them. All this was before the trials and suspicions of Imidicloprid on bees, i now avoid keeping bees near such treated fields especially if they bloom heavily and were treated way before bloom. It takes a while for imidicloprid to be taken up by the plant via the roots into the twigs, leaves, flush, bloom, etc........

It appears its the dosage and the crop's physiology of the bloom, Oranges blooms quick and at once, lemons all year round, also the timing of the application of Imidicloprid is a factor as well. They did an experiment in california in regards to Imidicloprid on bee health, (some good data) Lindcove research center. It was Orange blossom, does imidicloprid appear in the nectaries of the plant, yes it does, does it cause harm to a colony(reaches the LD50), yes, but it must reach certain ppb to do so. I will try and find the information online and post it here.

And Varroa.......I lose more bees to varroa than anything else including pesticides, and maybe a rival beek in my area. but pesticides are a lot more easier to blame than other issues such as mites, disease, poor forage which will lead into poor nutrition and succumb much more easier to viruses vecotred by varroa as a result of poor forage.

Re: The Case Against Imidicloprid

Originally Posted by Kieck

Sure, but from corn (maize)? From everything I've observed, they only seem to collect significant amounts of corn pollen in times of desperation. Your observations suggest that my generalization based on what I've seen in this region does not extend to that valley in Austria, at least.
...
Having said that, did you submit samples of honey and/or pollen from those collapsed hives for testing to see if clothianidin was detectable in them? Seems to me that that would have provided damning evidence, given everything else that you outlined here.

The finding that bee-collected pollen contained neonicotinoids is of particular concern because of the risks to newly-emerged nurse bees, which must feed upon pollen reserves in the hive immediately following emergence.

Pollen is the primary source of protein for honey bees, and is fed to larvae by nurse bees in the form of royal jelly.

A bee will consume 65 mg of pollen during the 10 day period it spends as a nurse bee [27], therefore a concentration of 20 ng/g (ppb) in pollen would correspond to a dose of 1.3 ng (65 mg 620 ng/g) or almost 50% of the oral LD50 of ca. 2.8 ng/bee [23].

Some of our pollen concentrations were even higher, although it is important to note that LD50 is measured as a one-time dose, while exposure through contaminated pollen would be spread out over the 10 d period and that there is likely substantial metabolic decay of the compounds during this time.

Lethal levels of insecticides in pollen are an obvious concern, but sublethal levels are also worthy of study as even slight behavioral effects may impact how affected bees carry
out important tasks such as brood rearing, orientation and communication.

My Austrian beekeeping friend didn't submit samples, but a large scale study confirmed the correlation between apiary deadouts and neonics:

DAFNE Project Nr. 100472
MELISSA

Investigations in the incidence of bee losses in corn and oilseed rape growing areas of Austria and possible correlations with bee diseases and the use of insecticidal plant protection products

Projektstart 01.03.2009
Projektende 15.03.2012

...
Summing up, the results of the MELISSA-project give evidence that in Austria regional clustered bee damages had occurred in the years 2009 – 2011, which were frequently associated with the use of maize and oilseed pumpkin seeds coated with insecticides, as proved by residue analysis.

Re: The Case Against Imidicloprid

When Varroa first came on the scene, did any of you ever just sit and watch a colony go down? What I recall is MASSIVE numbers of mites - in the thousands, mulitple per bee - and YES the colony died. Today the colony is dead - often blamed on Varroa when you can barely find mites without a sugar role. What's different today? Shouldn't the bees be getting more resistant to the mites with time rather than less. What's up here? (I guess you know where I stand.)

Re: The Case Against Imidicloprid

Another monitoring project with focus on neonicotinoid seed treatment products is the MELISSA Project
in Austria. In this project, particular attention is directed to the investigation of any damage to bees that is
reported in association of growing maize. (Latest report: Girsch and Moosbeckhofer, 2011). According to
preliminary results, the safety of neonicotinoid seed treatment products to honey bees can be sufficiently
ensured when the prescribed security measures for the use of these products are complied with.

As reported many times regarding the risk from Maize/corn, the main problems for bees are due to planter dust incidents during drilling. When seed drilling is done properly, the ongoing risks appear to be minimal.
A bigger risk with corn is monoculture, lack of bee forage and subsequent poor nutrition.

Re: The Case Against Imidicloprid

Originally Posted by grondeau

When Varroa first came on the scene, did any of you ever just sit and watch a colony go down? What I recall is MASSIVE numbers of mites - in the thousands, mulitple per bee - and YES the colony died. Today the colony is dead - often blamed on Varroa when you can barely find mites without a sugar role. What's different today?

Viruses. In the early days of varroa, the virus load in the hives was low, and the colony could survive with huge varroa populations. Now the virus load is way higher and it doesn't take much to tip the balance and kill the colony.

Re: The Case Against Imidicloprid

Originally Posted by Michael Palmer

Viruses. In the early days of varroa, the virus load in the hives was low, and the colony could survive with huge varroa populations. Now the virus load is way higher and it doesn't take much to tip the balance and kill the colony.

Exactly.

This paper by Martin et al explains how the arrival of varroa (in Hawaii) changes the viral landscape.
In the case of Deformed Wing Virus (DWV) there are several variants and when varroa arrives it leads to the dominance of the DWV strain which causes maximum damage to bees. The other strains of DWV are less harmful.

Re: The Case Against Imidicloprid

Posts #33 and 34 are really informative and make perfect sense to me. Grondeau is correct in that mite collapses really aren't as dramatic and easily recognizable as they were 20 years ago though clearly keeping mite numbers low are crucial to keeping your hives strong.

"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

Re: The Case Against Imidicloprid

Originally Posted by jonathan

A bigger risk with corn is monoculture, lack of bee forage and subsequent poor nutrition.

Monoculture has the biggest impact on bee foraging/health. The problem is beekeepers are dependant on other people to provide forage for their bees. We cannot dictate to other people, at least in the US today, how they manage their land.

Re: The Case Against Imidicloprid

Originally Posted by TWall

Monoculture has the biggest impact on bee foraging/health. The problem is beekeepers are dependant on other people to provide forage for their bees. We cannot dictate to other people, at least in the US today, how they manage their land.
Tom

That's true, but best practice could involve providing some intercropping with forage plants useful to bees and other pollinators. Beekeepers and landowners need to work together to help bee populations.

Re: The Case Against Imidicloprid

Originally Posted by jonathan

That's true, but best practice could involve providing some intercropping with forage plants useful to bees and other pollinators. Beekeepers and landowners need to work together to help bee populations.

Jonathan,

It has been almost 18 years since I've been to Ireland. But, agriculture is very different in the US and has changed recently to be come even more monoculture in nature. The fence rows of the past are gone and it is not unusual to see field planted almost to the roadside. Intercropping and leaving forage for pollinators is a thing of the past in a large part of the US.

There are areas such as the northeast and others where farms and fields are smaller and there is more diversity in crops and fields.

The other problem is most landowners don't farm their land or live on their farmland. In some areas of the country cash rent for farmland is over $500/ac. The farmer renting the land wants to farm all the land. The landowner wants rent paid on all the land. The end result is reduced bee/pollinator forage.

Re: The Case Against Imidicloprid

But yet every beek in the country is looking for that almond field or sunflower land for the bees......(okay not every one but you get my point) Really bad as a farmer to drive that combine around all the flowers to pick certian spots of corn so you can have bacon with your eggs...... but back to ima clorapids......

Re: The Case Against Imidicloprid

Originally Posted by gmcharlie

But yet every beek in the country is looking for that almond field or sunflower land for the bees......(okay not every one but you get my point) Really bad as a farmer to drive that combine around all the flowers to pick certian spots of corn so you can have bacon with your eggs...... but back to ima clorapids......